By Jim Beauchamp
2:48 PM PDT, April 22, 2014
The accident occurred where Adams, a three-lane, 45-mph road, transitions from having a bike lane to no bike lane.
On the same front page is a story about the Newport Bay Conservancy having concerns about the safety of Back Bay Drive and suggesting that runners and cyclists be banned from traveling south on the road.
Such a ban would force cyclists to ride south on Jamboree Road, which has three lanes of heavy traffic, a 55-mph speed limit and no bike lane. On the surface, this does not sound safer than riding on Back Bay Drive.
What is the basis for the safety concerns? The UC Berkeley TIMS accident database shows that in the 10 years from January 2003 to December 2012, the portion of Back Bay Driver under discussion was the scene of four fatal or severe bicycle accidents (out of 96 in all of Newport Beach). Three of the accidents involved a motor vehicle. During the 10 years there were no fatal or severe accidents involving pedestrians.
Clearly, if anyone has safety concerns, they should be for cyclists, and the easiest way to improve safety would be to ban motor vehicles from Back Bay Drive. Doing so would create a remarkable recreational resource, bringing out many more families and recreational cyclists, joggers and walkers. It would also make it possible to further separate pedestrians from cyclists.
How unsafe is Jamboree Road? During the same 10-year period, there were seven fatal or severe bike accidents on Jamboree Road from University Drive to Coast Highway. We would need ridership numbers for each road to be able to make a risk comparison.
Fortunately, there is a website that collects fitness cyclist's GPS data and then maps, compares and counts their rides. The GPS-equipped cyclists make a pretty large representative sample of the behavior of serious fitness cyclists. For example, last Saturday, 116 GPS-equipped cyclists logged data while riding south on Back Bay Drive, and 10 did the same riding south on Jamboree.
The data collected over the past three years show 100,000 GPS-equipped cyclists riding Back Bay and 11,000 riding Jamboree. So the relative risk per ride is .04 on Back Bay and .63 on Jamboree. Riding a bicycle on Jamboree is 16 times more dangerous as measured by fatal and severe accidents per rider than riding on Back Bay.
For comparison, during 10 years, a three-mile section of Coast Highway from the Bay Bridge to the west end of Newport Beach saw 16 fatal or severe accidents, and the three-year ridership count totaled about 100,000 equipped riders. For roughly equal distances, Back Bay is four times safer than Coast Highway, and Jamboree is four times more dangerous than Coast Highway.
By forcing hundreds of thousands of current southbound Back Bay riders to ride Jamboree, we should expect two fewer fatal or severe accidents on Back Bay over the next 10 years but 32 more fatal and severe accidents on Jamboree, according to my calculations.
JIM BEAUCHAMP lives in Corona del Mar.